Fix 500 error when rename repository

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

app/contexts/projects/update_context.rb

@@ -9,7 +9,7 @@ module Projects
       new_branch = params[:project].delete(:default_branch)
-      if project.repository.exists? && new_branch != project.default_branch
+      if project.repository.exists? && new_branch && new_branch != project.default_branch
         project.change_head(new_branch)
       end

features/project/project.feature

@@ -19,3 +19,8 @@ Feature: Project Feature
     And change project settings
     And I save project
     Then I should see project with new settings
+
+  Scenario: I change project path
+    When I visit edit project "Shop" page
+    And change project path settings
+    Then I should see project with new path settings

features/steps/project/project.rb

@@ -3,16 +3,25 @@ class ProjectFeature < Spinach::FeatureSteps
   include SharedProject
   include SharedPaths
-  And 'change project settings' do
+  step 'change project settings' do
     fill_in 'project_name', with: 'NewName'
     uncheck 'project_issues_enabled'
   end
-  And 'I save project' do
+  step 'I save project' do
     click_button 'Save changes'
   end
-  Then 'I should see project with new settings' do
+  step 'I should see project with new settings' do
     find_field('project_name').value.should == 'NewName'
   end
+
+  step 'change project path settings' do
+    fill_in "project_path", with: "new-path"
+    click_button "Rename"
+  end
+
+  step 'I should see project with new path settings' do
+    project.path.should == "new-path"
+  end
 end